1. Field of the Invention
The present invention relates to a new class of oil-soluble sulfur scavengers including N-alkyl hindered secondary or tertiary amines.
More particularly, the present invention relates a new class of oil-soluble sulfur scavengers including N-alkyl hindered secondary or tertiary amines and to a method for making the scavengers including contacting a sterically hindered primary or secondary amines with an aldehyde under conditions designed to promote alkylation of the amine.
2. Description of the Related Art
Many patents relate to sulfur scavengers for sweetening gas and liquid hydrocarbon streams such as U.S. Pat. Nos. 4,748,011; 4,978,512; 2,390,153; 3,856,921; 4,112,050; 4,112,051; 4,112,052; and Sartori and Savage “Sterically Hindered Amines for CO2 Removal from Gases” in I & EC FUNDAMENTALS, Vol. 2, No. 22 (1983).
Where sterically hindered amines such as aliphatic diamines and amino alcohols have previously been used in gas sweetening to form carbonates or bicarbonates from carbon dioxide, or to form sulfides or bisulfides from hydrogen sulfide reactions, such processes have typically involved a regeneration step to recover the carbon dioxide or hydrogen sulfide. During the regeneration step, the carbon dioxide or hydrogen sulfide is liberated from the process fluid. A process and composition are therefore needed that will convert hydrogen sulfide to a stable, nontoxic and noncorrosive form without a corresponding need for regeneration of process fluids.
Although many sulfur scavengers have been used and patented, there is still a need for new classes of sulfur scavengers, especially, sulfur scavengers that are effective in a triphasic environment (two liquid phases and a gas phase.